1. Field of the Invention
The present invention relates to an exhaust gas recirculation (EGR) system for an internal combustion engine and more particularly to a technique for furnishing an EGR path with an EGR sensor for detecting the amount of EGR.
2. Description of the Related Art
There is a known technique for precisely controlling an exhaust gas recirculation rate (EGR rate) in a cylinder of a diesel engine or other lean burn engines and reducing soot and NOx (nitrogen oxide) emissions from the engine in accordance, for instance, with engine operating conditions.
The technique for furnishing an EGR path with an EGR sensor for EGR flow rate detection for the purpose of precise detection or control of an EGR flow rate is disclosed, for instance, by JP-A-2006-214275, JP-A-2005-140024, and JP-A-2006-316706.
Further, a technique for furnishing the upstream side of an EGR cooler installed in an EGR path with a catalyst and trapping carbon or other elements in exhaust gas is disclosed, for instance, by JP-A-2003-65162, JP-A-2005-248777, and JP-A-2000-249003.